Generally, it is known that stresses induced on a transistor are important for boosting device performance. An n-channel metal oxide semiconductor field effect transistor (nMOSFET) will benefit from compressive stresses due to increases in electron mobility. A p-channel Metal Oxide Semiconductor Field Effect Transistor (pMOSFET) will benefit from tensile stresses due to increases in hole mobility. The type of substrate on which the polycrystalline silicon (also referred to as polysilicon) is grown influences the stresses created in the poly films. Polycrystalline silicon deposited on SiAlON (silicon aluminum oxynitride), for example, exhibits tensile stress. Polycrystalline silicon deposited on mullite (3Al2O3.2SiO2) or alumina (Al2O3), for example, exhibits compressive stress. Stress is generally larger at lower deposition temperatures due to smaller grain size and less columnar growth.